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Decapterus maruadsi is a typical representative of small pelagic fish characterized by fast growth rate, small body size, and high fecundity. It is a high-quality marine commercial fish with high nutritional value. However, the underlying genetics and genomics research focused on D. maruadsi is not comprehensive. Herein, a high-quality chromosome-level genome of a male D. maruadsi was assembled. The assembled genome length was 716.13 Mb with contig N50 of 19.70 Mb. Notably, we successfully anchored 95.73% contig sequences into 23 chromosomes with a total length of 685.54 Mb and a scaffold N50 of 30.77 Mb. A total of 22,716 protein-coding genes, 274.90 Mb repeat sequences, and 10,060 ncRNAs were predicted, among which 22,037 (97%) genes were successfully functionally annotated. The comparative genome analysis identified 459 unique, 73 expanded, and 52 contracted gene families. Moreover, 2804 genes were identified as candidates for positive selection, of which some that were related to the growth and development of bone, muscle, cardioid, and ovaries, such as some members of the TGF-β superfamily, were likely involved in the evolution of typical biological features in D. maruadsi. The study provides an accurate and complete chromosome-level reference genome for further genetic conservation, genomic-assisted breeding, and adaptive evolution research for D. maruadsi.

Single-event burnout and single-event leakage current (SELC) in silicon carbide (SiC) power devices induced by heavy ions severely limit their space application, and the underlying mechanism is still unclear. One fundamental problem is lack of high-resolution characterization of radiation damage in the irradiated SiC power devices, which is a crucial indicator of the related mechanism. In this Letter, high-resolution transmission electron microscopy (TEM) was used to characterize the radiation damage in the 1437.6 MeV 181Ta-irradiated SiC junction barrier Schottky diode under 200 V. The amorphous radiation damage with about 52 nm in diameter and 121 nm in length at the Schottky metal (Ti)–semiconductor (SiC) interface was observed. More importantly, in the damage site the atomic mixing of Ti, Si, and C was identified by electron energy loss spectroscopy and high-angle annular dark-field scanning TEM. It indicates that the melting of the Ti–SiC interface induced by localized Joule's heating is responsible for the amorphization and the possible formation of titanium silicide, titanium carbide, or ternary phases. The mushroom-like hillock in the Ti layer can be attributed to Rayleigh–Taylor instability, as another evidence for ever-happened localized melting near the Schottky interface. These modifications at nanoscale in turn cause localized degradation of the Schottky contact, resulting in permanent increase in leakage current. This experimental study provides very valuable clues for a thorough understanding of the SELC mechanism in SiC diodes. [ABSTRACT FROM AUTHOR]

The high‐pressure behavior of hafnon has been systematically investigated by combining in situ synchrotron X‐ray diffraction, Raman, high‐resolution transmission electron microscopy (HRTEM) techniques, and theoretical simulations. Hafnon starts phase transition at 26.6 GPa and completes the transition to an irreversible scheelite phase (I41/a$I{4}_{1}/a$, Z = 4, a0 = 4.712 Å, and c0 = 10.378 Å) at ∼45 GPa. The HRTEM observation of an interface between hafnon and scheelite phases allows atomic scale understanding of the transition process with a relationship of (200)h‖(112)s, (002¯)h∥(1¯10)s$(00\overline{2})_{\mathrm{h}}\Vert (\overline{1}10)_{\mathrm{s}}$//, and [010]h∥[1¯1¯1]s$[010]_{\mathrm{h}}\Vert [\overline{1}\;\overline{1}\;1]_{\mathrm{s}}$. Hafnon shows a significantly lower transition pressure (∼12.6 GPa), as calculated from the relative enthalpies, than the measured pressure (∼26 GPa), indicating a kinetically hindered process involved in the transition. A high pressure low symmetry phase in hafnon (I4¯2d$I{\overline{4}}_{2}d$) is identified by the simultaneous appearance of two Raman modes (∼75 and 450 cm−1) at 26.6 GPa and their subsequent simultaneous disappearance at 36.7 GPa. These results are important to understanding the mechanism of the zircon‐scheelite transition for both zircon and hafnon. [ABSTRACT FROM AUTHOR]

The effect of defects on the high‐pressure behavior of materials is fundamental to understanding and designing materials for extreme environments. Previous work has demonstrated that radiation damage can enhance phase stability or alter the transformation pathway. Here, we report the high‐pressure phase stability of CeO2 irradiated by swift heavy ions. CeO2 is of particular interest because it can be used as a non‐radioactive surrogate for UO2 and PuO2. High‐pressure Raman spectroscopy shows that low‐fluence ion irradiated CeO2 exhibits nearly the same high‐pressure behavior as unirradiated CeO2; whereas, after high‐fluence irradiation, the phase stability of CeO2 is significantly enhanced, with the critical phase transition pressure increased from 31.7 to 37.3 GPa and only about 7% high‐pressure phase transition fraction at 45.1 GPa. In comparison with the high‐pressure Raman results of pre‐irradiated CeO2 before and after 573, 1073, and 1 273 K annealing in air, we propose that large interstitial‐type defect clusters, such as dislocation loops formed in heavily‐irradiated CeO2, are predominately responsible for the increased phase stability at high pressures. [ABSTRACT FROM AUTHOR]

We report on the first observation of fine structure of latent tracks in rutile TiO 2 , which changes from cylinder to dumbbell-shape and then to sandglass-shape as a function of the ion path length. Moreover, the cone length of the track was found to be dependent on electronic energy loss. The results indicate that outflow of the thermal spike-induced molten phase produces the hillocks on surface and the void-rich zone near surface after epitaxial recrystallization due to material deficit, while at a deep depth, the lack of efficient outflow and recrystallization result in the absence of tracks. We propose that the various morphologies of tracks in rutile TiO 2 are a consequence of the molten phase outflow and recrystallization during rapid cooling down. [ABSTRACT FROM AUTHOR]

of lubricant phase into thermally sprayed coating while avoids high-temperature ablation is still a challenge. Here, vacuum impregnation and hydrothermal reaction, acted as a post-treatment process, was applied to synthesize MoS 2 phase on and within high-entropy alloy (HEA) coating. The as-synthesized MoS 2 phase with high purity and spherical shape distributed in the pores and finally formed a thin layer on coating surface. Compared to the single HEA coating, coefficient of friction (COF) and wear rate (Q) of the HEA/MoS 2 composite coatings possessed a significantly reduction, i.e 87.2% and 75.6% reduction in COF and Q at 2 N, respectively. Besides, owing to the formation of lubricating film during the sliding process, the composite coating had a more stable sliding process. At the same time, the doped MoS 2 played a positive role in reducing abrasive- and adhesive wears for both coating and coupling ball. Since the lubricating film can be continuously replenished and repaired, the HEA/MoS 2 self-lubricating coatings maintained a good chemical stability and provided a relatively good wear properties. • Hydrothermal reaction, as a post-process treatment, is combined with thermal spraying to prepare self-lubricant coating. • MoS 2 with high purity dramatically decreases the COF by over 64.3%. • MoS 2 layer presents good chemical stability under friction of reciprocation. [ABSTRACT FROM AUTHOR]

Fission events in minerals create a damage track, which provides critical information for events that occur over a wide range of time scales, ranging from nuclear fission events (10−20 to 10−12 seconds) to track formation (10−17 to 10−9 seconds) and geological processes (millions of years). However, the site where fission occurs has never been identified along a fission track, as it is long (∼20 μm), thin (diameter <10 nm), and randomly oriented in the mineral matrix. Here, we, for the first time, observe an unexpectedly narrower track diameter (∼1 nm), rather than the conventionally assumed largest diameter, near the fission-event site by a novel technique that confines fission events to the sample surface. The low-charge states of fission fragments produce the narrower track nearest the fission site due to the instantaneous partitioning of negatively charged electrons between two positively charged fission fragments, roughly scaling to their proton numbers. Because a narrower fission track is easier to anneal, the nanostructure nearest the fission site provides spatial information necessary for understanding the atomic-scale mechanisms of track formation and track annealing, with significant implications for fission track thermochronology. • A fission track has a surprisingly narrower diameter at the fission site. • The low-charge-state fissioned atoms produce the narrower track diameter. • Electrons instantly partition between two fission fragments at the fission site. • The narrower fission tracks at the fission site would be easier to anneal. • Track nanostructure bridges the gap between unetched and etched fission tracks. [ABSTRACT FROM AUTHOR]